Drive for a movable furniture element

0001This application is a Continuation of International Application No. PCT/AT2008/000152, filed Apr. 25, 2008.

BACKGROUND OF THE INVENTION

0002The present invention concerns a drive for a movable furniture part, comprising an adjusting member for moving the furniture part and a motor for driving the adjusting member, wherein the adjusting member and the furniture part are at times movable independently of each other.

0003Drives of the general kind set forth are already known, in which the position or movement parameters derived therefrom of the adjusting member or the movable furniture part can be determined by way of a position measuring device.

0004For example WO 2006/017864 A1 on pages 5 through 6 (fourth variant of the invention described in WO 2006/017864 A1) describes a drive for a movable furniture part comprising a position measuring device by which the position of the adjusting member (ejection lever) can be determined. In addition, the above-indicated specification on page 7 thereof describes the possibility of coupling the position measuring device to the furniture part itself, instead of to the adjusting member. In the embodiment shown in <figref idref="DRAWINGS">FIGS. 18 and 20</figref>, that is effected either by way of a spring-loaded thrust member or by way of an entrainment member which can be coupled to the movable furniture part over a certain distance.

0005The state of the art suffers from the problem that it is not possible to detect the position or movement parameters derived therefrom selectively or simultaneously both for the furniture part and also for the adjusting member. More specifically, the position and movement cannot be detected independently of whether the adjusting member is or is not just in contact with the furniture part.

0006The object of the invention is to overcome that problem, and is attained by a drive having the features described below.

0007There can be various reasons why the adjusting member and the furniture part are at times movable independently of each other. For example, the adjusting member, for moving the furniture part, can loosely contact the furniture part. That situation arises when the adjusting member is in the form of an ejection lever or thrust member. More specifically, the ejection lever or thrust member bears against the furniture part only over its pivotal or extension travel.

0008It can, however, also be the case that the adjusting member in itself is fixedly connected to the furniture part but a coupling is arranged in the drive train between the motor which drives the adjusting member and the furniture part, wherein the drive train can be disengaged by the coupling. It may be desirable, for example, if the movable furniture part is movable manually by a user without—in that case—the user being impeded by the motor. That is advantageous if the motor is defective or the user for example wants a higher speed than that of the furniture part when driven by the motor.

0009It can, however, also be the case that the coupling is in the form of an overload coupling to avoid damage to or destruction of the adjusting member or the motor. Without such an overload coupling, the adjusting member, when the movable furniture part is loaded with excessive forces, can transmit those forces to the motor or a transmission.

0010In regard to all those possible options, it is possible with a drive according to the invention to determine the position or movement parameters derived therefrom (such as speed or acceleration) of the adjusting member and/or the furniture part, even if the adjusting member and the furniture part are just moving independently of each other.

0011The fact that the position or movement parameters derived therefrom of the furniture part can be continuously determined means that it is, for example, possible to constantly maintain a touch-latch functionality with respect to the drive. This means that a user can cause activation of the motor by the application of a force to the furniture part and the change in position or speed of the furniture part, that is caused thereby. That is desirable, in particular, when the motor is active only over a part of the total travel of the furniture part in order to again trigger the motor.

0012The effect of determining the position or derived movement parameters of the adjusting member can also be used on the one hand to implement a touch-latch functionality. In this case, for example, the motor is activated upon a change in the position or speed of the adjusting member.

0013On the other hand, the motor can also be intended by way of the adjusting member to implement a predetermined travel, speed, or acceleration profile for the furniture part. To permit the dependency on the position or speed or acceleration in regulated relationship, it will be appreciated that there must be a suitable position measuring device and possibly a clock and a computing unit.

0014It is also possible to provide for collision monitoring by using the position measuring device. The position (location or travel) of the movable furniture part is measured in that case and monitored by a control or regulating device for a change in speed or acceleration. The operation of ascertaining the speed or acceleration of the movable furniture part can be effected, for example, by forming the first or second derivative of the position in dependence on time. If the change in speed or acceleration differs from a reference value which was established earlier, then the motor can be switched off. Examples of collisions include a user who is standing under a movable item of furniture in the form of a flap and who blocks the closing movement of the flap, or an article projecting from a body or carcass of an item of furniture and which prevents a drawer or flap from closing.

0015In a particularly preferred embodiment of the invention, the position measuring device can have at least one potentiometer. Particularly preferably, however, there are two potentiometers, in which case a respective potentiometer is associated with the adjusting member and the furniture part, respectively. Absolute position determination can be effected by potentiometers. However, purely incremental position determination may also be adequate for the invention.

0016It is particularly preferably provided that the motor is in the form of an electric motor.

0017If control or regulation of the drive is desired, it will be appreciated that a control or regulating device must be provided, to which the signals of the position measuring device can be passed.

0018It will be self-evident that the position measuring device can physically also be in the form of two components which are spatially separate from each other. Alternatively, it is possible to provide a single component with which there are associated two measuring sensors (for the adjusting member and the furniture part) which operate separately from each other.

BRIEF DESCRIPTION OF THE DRAWINGS

0019Further advantages and details of the invention will be apparent from the Figures and the related specific description. In the drawings:

0020<figref idref="DRAWINGS">FIGS. 1 through 4</figref> show various views of an embodiment of the invention in a flap drive system, and

0021<figref idref="DRAWINGS">FIG. 5</figref> shows a perspective view of a body or carcass of an item of furniture with a fitted flap drive system as shown in <figref idref="DRAWINGS">FIGS. 1 through 4</figref>.

DETAILED DESCRIPTION OF THE INVENTION

0022<figref idref="DRAWINGS">FIGS. 1 through 4</figref> show an embodiment of the invention incorporated into a flap drive system <b>1</b>.

0023In this case, <figref idref="DRAWINGS">FIG. 1</figref> shows a cover surface <b>24</b> of a mechanical adjusting unit (adjusting member) <b>2</b> which is not shown in greater detail in <figref idref="DRAWINGS">FIG. 2</figref>. The cover surface <b>24</b> has two projections <b>241</b> which serve to suspend (support) the base plate <b>39</b> of an electric drive <b>3</b>. In that case, it is suspended by lugs <b>391</b>. After it has been suspended in place, the electric drive <b>3</b> and the mechanical adjusting unit (adjusting member) <b>2</b> can be screwed together by screws, in which case (in this embodiment) the cover surface <b>24</b> has suitable receiving means <b>242</b> for the screws. It is further possible to see in <figref idref="DRAWINGS">FIG. 2</figref> the transmission <b>33</b>, the electric motor <b>31</b>, and a coupling <b>34</b> connecting those two components together (in this embodiment, it is of a mechanically flexible nature). In addition, fixed on the base plate <b>39</b> is a circuit board <b>38</b> having the circuits of a control or regulating unit.

0024The interface <b>6</b> is here in the form of the central spindle <b>6</b>′ of the electric drive <b>3</b> and a receiving means (not shown) for the spindle <b>6</b>′, which is arranged behind a receiving opening <b>6</b>″ on the adjusting member <b>2</b>.

0025<figref idref="DRAWINGS">FIG. 2</figref> shows the mechanical adjusting unit (adjusting member) <b>2</b> as an overall unit, as can already be fixed in a body or carcass of an item of furniture (not shown in <figref idref="DRAWINGS">FIG. 2</figref>). In this case, the mechanical adjusting unit <b>2</b> has an adjusting arm <b>21</b> which is subjected to the action of a spring storage device <b>22</b> (here: a spring pack) which is not shown in detail in <figref idref="DRAWINGS">FIG. 2</figref> but which corresponds to the state of the art device.

0026The housing of the adjusting member <b>2</b> has a base surface <b>23</b> with which the adjusting member <b>2</b> can be fixed to a carcass or body of an item of furniture. Arranged at a spacing (spaced apart) therefrom and substantially parallel thereto is the cover surface <b>24</b> which serves for fixing the electric drive <b>3</b> to the adjusting unit <b>2</b>.

0027In relation to the electric drive <b>3</b>, <figref idref="DRAWINGS">FIG. 2</figref> in comparison with <figref idref="DRAWINGS">FIG. 1</figref> shows a potentiometer <b>37</b> co-operating with the end stage of the transmission <b>33</b> (see, in that respect, the exploded view in <figref idref="DRAWINGS">FIG. 3</figref>). The position of the adjusting arm <b>21</b> and thus the position of the flap <b>4</b> (not shown in <figref idref="DRAWINGS">FIG. 2</figref>) can be determined by the potentiometer <b>37</b> as the end stage of the transmission <b>33</b> co-operates with the adjusting arm <b>21</b> without slippage via the interface <b>6</b> (not shown in <figref idref="DRAWINGS">FIG. 2</figref>), even if the adjusting member (and motor) operate independently of the adjusting arm <b>21</b> and furniture part <b>4</b>.

0028A second potentiometer is not separately shown in the Figures, that second potentiometer being mounted directly on the circuit board <b>38</b> by suitable circuits. By way of the second potentiometer, it is possible to determine the position of the adjusting member <b>2</b>, via the drive output of the electric motor <b>31</b>.

0029<figref idref="DRAWINGS">FIG. 3</figref> shows the actual arrangement of the potentiometer <b>37</b> relative to the transmission <b>33</b>. In this case, a toothed ring <b>371</b> is non-rotatably connected to the end stage of the transmission <b>33</b> and co-operates with a gear <b>372</b> in such a way that there is a 2:1 transmission ratio with respect to the movement of the end stage of the transmission <b>33</b> to the gear <b>372</b>. That means that the measuring range of the potentiometer <b>37</b> with which the gear <b>372</b> co-operates can be better utilized.

0030It can further be seen from <figref idref="DRAWINGS">FIG. 3</figref> that a pin <b>312</b> is fitted in place at the drive output <b>311</b> of the electric motor <b>31</b>, and the pin <b>312</b> is fitted into the coupling <b>34</b> (here: a mechanically flexible tube coupling). Arranged on the other side of the coupling <b>34</b> in a housing <b>313</b> is a worm gear co-operating with the first stage of the transmission <b>33</b>.

0031The electric drive <b>3</b> further has an overload coupling <b>331</b> and a freewheel coupling <b>35</b> within the drive train between the motor <b>31</b> and the adjusting arm <b>21</b> of the adjusting member <b>2</b> which is fixed to the flap <b>4</b>. In that case, the overload coupling <b>331</b> can disconnect the transmission <b>33</b> from the adjusting member <b>2</b> to prevent unwanted destruction of the gears of the transmission <b>33</b> caused by an excessive loading acting on the adjusting arm <b>21</b>. The freewheel coupling <b>35</b> permits intervention on the part of a user when the flap <b>4</b> is being driven without being impeded in that respect by the motor <b>31</b>. In other words, as with the overload coupling <b>331</b>, the freewheel coupling <b>35</b> allows the flap <b>4</b> to be disengaged (disconnected) from the motor <b>31</b>, if necessary.

0032<figref idref="DRAWINGS">FIG. 4</figref> again shows a perspective view of the flap drive system <b>1</b> as shown in previous <figref idref="DRAWINGS">FIGS. 1 through 3</figref>, wherein the electric drive <b>3</b> is fixed in the form of a self-contained component to the mechanical adjusting member <b>2</b>.

0033Although it is advantageous for the electric drive <b>3</b> to be fixed to an adjusting unit <b>2</b> even when the adjusting unit <b>2</b> is already mounted to a body or carcass <b>5</b> of an item of furniture (See <figref idref="DRAWINGS">FIG. 5</figref>), it will be appreciated that pre-fabrication of the flap drive <b>1</b> can also be effected in the form shown in <figref idref="DRAWINGS">FIG. 4</figref>.

0034<figref idref="DRAWINGS">FIG. 5</figref> shows a body or carcass <b>5</b> of an item of furniture with a flap <b>4</b> mounted movably thereto and a flap drive system <b>1</b> as shown in <figref idref="DRAWINGS">FIGS. 1 through 4</figref>.